Method for preventing formation of scale or incrustations in steam boilers and the like



Feb. 2, 1932. G. s. HESSENBRUCH 1,

METHOD FOR PREVENTING FORMATION OF SCALE OR INCRUSTATIONS IN STEAM BOILERS AND THE LIKE Filed Oct. 26, 1928 Patented Feb. 2, 1932 "It FFPCE PATENT GEORGE S. HESSENBRUCH, OF WEBSTER GROVES, MISSOURI, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO EMIL NATHAN, OF ST. LOUIS, MISSOURI METHOD EOE PREVENTING FORMATION or SCALE on. INGRUSTATIONS IN STEAM BOILERS AND THE LIKE Application filed October 26, 1928. Serial No. 315,189.

This invention relates to an improvement in methods for prevention of the formatlon of scale or incrustation in steam boilers and the like, and consists in the novel procedure hereinafter. disclosed.

I am aware that numerous expedients have been suggested for preventing formation of scale or incrustation in steam boilers for locomotives or stationary installations, and in and on boiler accessories such as condensers, feed water heaters, piping and the like. The prior art contains examples of the use of direct current and also the use of alternating current. But, in the prior art methods it has 1 been usual to employ the shell of the container as one of the terminals of the external electric circuit and, because of the difficulty in these methods of obtaining an equal distribution and flow of current through the water that carries the impurities, the success of the previous methods has been varying and little has been accomplished in the practical prevention of the formation of scale and incrustation under various conditions of the installations and of the varying degree of impurities carried in the feed water.

I have discovered that by applying to the water container an alternating current by a circuit in which the terminals comprise, for

one pole, an elongated distributor arranged in the upper part of the container and, for the other pole, a. plurality of terminals immersed in the liquid in such a manner that there is no electrical contact with the shell of the container, I have been enabled to obtain exceedingly satisfactory practical results.

' I am aware of the several theories that have been advanced in connection with the use of alternating and direct current and their action upon the content of the feed water and, while I do not deem it important.

to set forth these various theories, I hold the view that the alternating current applied ac cording to my improved method acts to depolarize the particles suspended 1n the water and, through the pulsation of the alternating current directly applied to the electrolyte, these particles are dropped from solution and suspension in the water so that the container may be readily cleansed. Thus, by the antiplating action set up in the electrolyte any incrustations previously formed are softened and broken from their adhesion with the container wall.

I have found also that in order to accomplish practical results the one pole of the applied current should be arranged substantially co-extensive with the length of the container, and the other pole of the circuit connected with electrodes near the bottom of the container and distributed throughout the area of the bottom section of the container, although these limitations of points of application of the applied current are not, under all circumstances, essential.

Therefore, the general object of my invention may be stated to be the provision of a method for preventing the formation of scale or incrustation in all types of steam boilers,

boiler accessories such as condensers, feed water heaters, piping and the like, by applying to the Water in the container an externally generated current, one pole of which is connected with a distributor and the other pole of which is connected with a plurality of electrodes. The distributor at the one pole and the electrodes at the other pole are both immersed in the water or electrolyte, so that both poles are completely electrically insulated from the container shell.

In the accompanying drawings there is illustrated one practical embodiment of an apparatus for practicing theinvention.

Fig. 1 is a longitudinal section of a locomotive boiler with the circuit diagrammatically shown in connection therewith.

Fig. 2 is a cross section substantially on the line 2-2 of Fig. 1.

Fig. 3 is a cross section substantially on the line 33 of Fig. 1.

In the illustrative embodiment of my invention 1 indicates the boiler shell of a locomotive boiler of usual construction. Across the upper portion of the boiler shell is a distributor that comprises longitudinal members 2. preferably in the form of pipes or tubing. The members 2 are suspended in the shell by hangers. Each hanger comprises spool insulators 3 with a bolt 4 that passes through the members 2 and through the axial opening of the insulators. A strap 5 connects the insulator to which the members 2 are attached with a second insulator 6, said last named insulator being supported by a bracket 7 attached to the under face of the top wall of the boiler shell. A bolt 8 serves to connect the insulator 6 with the bracket 7, said bolt 8 passing through the axis thereof. There is thus provided asuspension means for the distributor constituting one of the electrodes of the applied circuit which serves electrically to insulate the distributor from the shell of the boiler. It will be noted that the distributor is sufficiently remote from the top of the shell so that it will be below the normal water line 9 under operative conditions.

In a locomotive boiler installation, where the members 2 are closely adjacent to the metallic parts in the boiler shell, it is advisable to supply an insulator, as indicated at 10, to prevent contact of the distributor with any of the metal parts of the boiler.

One of the members 2 is electrically connected by a cable 11 with a plug 12, said plug 12 entering through the wall of the shell of the boiler from which it is electrically insulated. The plug 12 is electrically connected with a line lead 13 to one pole 14 of a suitable source of alternating current, for example, a generator 15. It will, of course, be understood that the two members 2 are cross connected by a jumper 16, thereby energizing both members 2 from the source of electrical supply.

It should be understood that the electric machine for applying the external current maybe of any conventional design, a suitable mac'hme for this purpose being a turbo-generator developing an alternating current of approximately one hundred and ten volts and from eight to twenty amperes at one hundred and twenty cycles. The pole 17 of the electrio machine is connected with a line lead 18 which, 1n turn, connects with a plurality of plugs 19, said plugs being widely distributed across the bottom section of the shell of the boller and entering through the wall thereof. The plugs 19 are electrically insulatedfrom the sh ell and project into the shell relatively a considerable distance. The energized member of the plugs may be of any suitable metal, for example, copper or brass.

The application to the container of the applied current in the. manner described affords a successful means of preventing the formation of scale and loosening incrustations on the shell.

It should be understood that I do not confine myself to the limits of voltage and amperage hereinbefore mentioned, nor to the number of cycles of the electric machine. It may be said that in experiments it has been noted that an increase of cycles of the electric machine accelerates the action of the current on the impurities in the feed water. The selection of voltage, amperages, and cycles of the electric machine are factors that may be varied in practice and depend, to some degree, upon the volume of water, extent of shell surface and amount of impurities contained in the feed water.

I am aware that the invention may be modified within equivalent, limits without departure from the spirit and scope thereof. I do not limit myself therefore to exact details, but what I claim and desire to secure by Letters Patent is 2- 1. The method of preventing formation of scale and incrustation in steam boilers or the like, which comprises the direct application of an alternating current, the electrodes of the circuit being completely electrically insulated from the shell of the boiler, and being immersed in the water contained therein.

2. The method of preventing formation of scale and incrustations in steam boilers and the like, which consists in energizing the Water by an alternating current passed through the water acting as an electrolyte from electrodes insulated from the boiler shell and distributed at separated points of the water container.

3. The method of preventing scale and incrustation in steam boilers and the like, which consists in maintaining an external alternating current circuit, and applying the cir- -cuit to the water in the boiler by electrodes insulated from the boiler shell.

4. The method of preventing formation of scale and incrustation in steam boilers and the like, which consists in establishing through the water as an electrolyte an alternating current circuit generated from an external source and electrically insulated from the water container.

5. The method of preventing formation of scale and incrustations in steam boilers or the like, which consists in applying to a GEORGE S. HESSENBRUCH. 

